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WACCAMAW AREAWIDE WATER QUALITY MANAGEMENT PLAN 1986 UPDATE Prepared by Waccamaw Regional Planning and Deve'lopment Coundil June 1986 GB 991 W33 W33 1986 WACCAMAW AREAWIDE WATER QUALITY MANAGEMENT PLAN@ KI 1986 UPDATE 40 Prepared by Waccamaw Regional Planning and Development Council June 1986 Major funding was provided by the South Carolina Coastal Council from resources made available by the National Oceanic and Atmospheric Agency. Project supervision and technical assistance was provided by the South Carolina Department of Health and Environmental Control. P R E F A C E This plan update consists of three parts, done at different times, and consolidated herewith for public participation and approval purposes by the several agencies involved. Early funding for the first two parts was provided by the Environmental Protection Agency. The third part, which emphasizes storm runoff impacts on water quality in specified rapid growth areas, was supervised by the South Carolina Department of Health and Environmental Control (DHEC) in accordance with a contract with the South Carolina Coastal Council. This plan update was produced by the Waccamaw Regional Planning and Development Council under a sub-contract with DHEC. T A B L E 0 F C 0 N T E N T S UPDATE III - June 1986 Summary Wasteload Allocation and NPS Coordination Strategy Methodology for Predicting the Impact of NPS Pollution on Water Quality Potential Impact of Pollution Loading on Assimilative Capacity Future Water Quality Monitoring Needs for Entire Coastal Region UPDATE II - April 1986 Introduction Total Maximum Daily Loads Nonpoint Source Controls Regulatory Programs Management Agencies Municipal Needs Population Projections Land Use Projections Discharger Inventory APPENDIX I - January 1981 Update Introduction Conclusions and Recommendations APPENDIX II - Memorandum of Agreement (208 Plan Conformance Certification) APPENDIX III - Grand Strand 201 Update APPENDIX IV - List of Dischargers APPENDIX 'V - Maps A. Rapid Growth Areas B. Monitoring Stations and Stream Classificaitons (overlay) C. Stream Segments Potentially Impaired by NPS D. Significant Natural Resource Areas and Point Source Discharges SUNNARY 208 UPDATE I I I Prepared by Waccamew Regional Planning And Development Council JUNE 1986 SUMMARY 208 UPDATE III The 208 Update III concentrates on the nonpoint runoff impact issue. As part of this update a Methodology to assess Nonpoint Pollution Impacts on Water Quality was developed. This was based on a Nonpoint Pollution Literature Survey. The Waccamaw Region does not have a model capable of simulating NPS impacts on water quality as do the two other Coastal COGS. The Waccamaw Region's waters do not meet the Standard of 5 mg/l DO even without any local dischargers or local nonpoint inputs. This is the natural system. The,fact that these local waters don't meet the standard means that the assimilative capacity of the local rivers is low and any potential nonpoint pollution could reduce the assimilative capacity more. All existing Waccamaw Grand Strand area dischargers are at their assimilative capacities now. There is no way with existing tools, to predict the impact of NPS on water quality, however, the newly installed USGS water quality monitors will give a much better picture if they can be operated for another year. A new analysis of NPS loadings contributed by present and future development was conducted for this plan and the conclusions of this analysis were that BOD loadings from an intense summer storm will increase about 60% by 2005 if no controls are implemented to control the runoff. There is no way to translate this to water quality impacts. The volume of runoff increases up to 1000% in this type storm and while the BOD loading may increase, the actual concentrations may decline due to the greater volume of water. Water quality problems are sure to arise in waters where stormwater is the majority of@low or is poorly diluted. The primary issue is duration and intensity of these impacts. As a result of assessing point source allocations, NPS loadings and potential and existing water quality problems, three River segments in this Region were 2 designated severe potential NPS impairment with the potential for waste load allocation impacts. The primary area of concern was the ICWW from Socastee to NMB where MB and NMB get their drinking water and there is extensive growth expected with no NPS controls since this area is in Horry County. The other areas of concern are the Waccamaw River from Conway to ICWW where there are two dischargers and expansive growth is expected. The third area from above Wachesaw to 'C' Plant receives the greatest point source loadings and any decrease in assimilative capacity of this segment wo.uld be extremely costly to the dischargers. As a result of these significant actual and potential impacts a "Wasteload Allocation and NPS Coordination. Strategy" was developed. This strategy outlines a proposal to coordinate an evaluation and implementation plan between the Coastal Council, DHEC, and Waccamaw 208 staff. The primary NPS impact along the Grand Strand is the bacterial contamination of shellfishing areas. All Grand Strand shellfish areas are closed at least conditionally and most are prohibited to shellfishing all the time. Management of runoff to shellfishing areas is a documented problem and must be addressed strongly and directly. Management Agencies: The Grand Strand Water and Sewer Authority is recommended for designation to replace the Horry County and Sewer Authority. The West Horry 201 is prepared for amendment to provide for Innovative and Alternative Sewer Systems with land application of effluent for the Longs and Bucksport communities as outlined in the Wastewater Facilities Plan for these communities. UPDATE I I I WACCAMAW 208 AREAWIDE WATER QUALITY MANAGEMENT PLAN WACCAMAW REGIONAL PLANNING AND DEVELOPMENT COUNCIL JUNE 1986 208 UPDATE III Nonpoint Source Impacts The Waccamaw 208 Areawide Water Quality Managment Plan (1978) has previously identified stormwater runoff. as a pollution concern particularly based on the work done through the Nationwide Urban Runoff Program (NURP). The primary focus of the Waccamaw NURP was bacteriological impacts of stormwater on beaches. This information also has implications for runoff to shellfishing areas. The initial 208 Plan completed and calibrated a mathematical model of the Grand Strand area from Winyah Bay to Little River including the Pee Dee and Wacdamaw Rivers. This model, however, is basically a "steady state" model not capable of dynamic changes such as stormwater inputs. The 1978 208 analysis of nonpoint pollution (Appendix 6 and 7) only considered the annual nonpoint loadings contributed by large sub-basin areas. While these BOD loadings were predicted to increase by 35% there was no analysis of the possible water quality impacts of these increased NPS loadings. All wastewater dischargers in the rapid growth areas delineated by the attached map discharge to waters which do not meet the presently defined water quality standard of 5.0 mg/l dissolved oxygen (D.O.). The fact that the Waccamaw Region's waters do not meet the defined standard is shown by an analysis of DHEC primary and secondary ambient monitoring stations along with special intensive surveys conducted in the area, and these low D.O. levels are also predicted by the 208's well-documented Waccamaw Intracoastal Waterway Model. Previous to the newlyado-pted DHEC standards dischargers were allowed to reduce the D.O. to 4 mg/1 D.O., now new dischargers to these waters are required to adhere to the "0.1 mg/l D.O. rule." This rule in the water quality standards allows discharger in waters which do not naturally meet the standard of 5 mg/l D.O. to bring the ambient background D.O. level down no more than 0.1 mg/l of D.O. This new standard represents a significant change from previous requirements. How this might affect increased or new wasteload requests is not clear and should be addressed in a comprehensive Regional Wasteload Strategy so that all Regional dischargers can have a clear view of wasteload requirements. A complication in any long-term water quality assessment policy is the possible NPS impacts from areas of uncontrolled development. The dischargers located in the rapid growth areas discharge to waters which also receive stormwater runoff from the developments they are designed to serve. Another factor in any assessment is that some discha@gers which have stormwater controls in their area discharge to waters which may be already impacted by runoff from areas outside their jurisdiction. The role of the local 208 agency according to the 1986 Memorandum of Agreement is to balance the point source assimilative capacity allocations against the possible NPS impacts that the area may be having on water quality. It will, however, not be possible to accurately assess this factor of NPS impacts until a more detailed analysis of water quality impacts is understood. In order to better understand the possible NPS impacts on overall water quality in the Waccamaw Region, an analysis was conducted to assess the type of loadings expected from future development. The Waccamaw 208's original studies and resulting 1978 plan evaluated the runoff of three areas of different land uses. From this information a simplified desk top technique was developed toprojectthe impacts of land-use changes on runoff volume and pollutant concentration. The S.T.O.R.M. model was then utilized to develop runoff curves for varying SCS curve numbers and varying storm return frequencies. The calibrated S.T.O.R.M. model was also used to estimate changes in pollutant loadings from changes in land use. The loading data was used to generate 6 annual pollutant loads and these loads were then predicted based upon future land use changes predicted to occur in each drainage areas. The basins were then ranked according to pollution potential. While this ranking of NPS potential based upon annual pollutant loadings is helpful to understanding the long-term increases of pollutant loading in the region this does not help in predicting any water quality impacts of these changes. There is no discussion of the magnitude of these locally generated loads as compared to loads entering the region, nor Is there any combination of NPS outputs with the water quality simulation model. There was also no attempt made to predict impacts on water quality or Waste Load Allocations. The Waccamaw ICWW model Is not capable of simulating drynamic iMPUtS Such as stormwater making it difficult to predict ang direct water quality impacts of non point sources without a new sophisticated and costig model. Based upon an evaluation of existing conditions in the Waccamaw Region the available assimilative capacity has been allocated to almost all dischargers in the Grand Strand area and those not get at assimilative capacity are expected to reach that capacity with their future projected increases. A listing of discharges in the growth area and the remaining assimilative capacity follows: City of Conway - Unknown GSW&SA Central - 0 Remaining GSW&SA and MO City - 0 Remaining GSW&SA 'A' - 0 Remaining city of NNO - 0 Remaining GSW&SA 'C' 0 Remaining City of Georgetown & I.P. 41@ 7r..".: 0 Remaining 7 With the exception of Grand Strand's Central Plant all the assimilative capacities are allocated for low flow at 30QIO or 7QlO flow regime. The Central facility's allocation was based on hUdrograph related loadings with essentially no loadings permitted at low flows but the more flow in the river the more waste loading allowed. The water quality evaluation for this facility was also based on the "new" standard of allowing U. 1mgPD.O. deficit in waters not meeting standards of 5mg/l. The Georgetown County 'C' Plant and the combined GSW&SA and NO discharge are based upon the 1976 Grand Strand EIS and the 208 model which were completed at the same time. The target D.O. for these allocations was 4 mg/l D.O. How the change in standards and policy may affect future permit reissuance Is unclear. Another potential problem is that with the assimilative capacity of streams completely allocated to point sources there is a potential for nonpoint sources of pollution to affect these allocations. As described in the Methodology and Literature section it is not possible, according to DHEC, to predict the impact of NPS on low,f low conditions without -a'dynamit model. There are too many variables to isolate or predict impacts. As rainfall events occur, the flows change which-change reaction rates as well as other factors. The recently Installed USGS continuous monitoring stations identified on the monitoring station map overlay is providing information on the D.O., PH, conductivity, temperature, and stage (flow) throughout the Waccamaw/Pee Dee system on the Grand Strand in 15 minute intervals. This is the first time these type stations have been located In a coordinated manner to address Regional water quality issues. The information from these stations will be invaluable to understanding the water quality changes occuring with time. These station will be coordinated with rainfall data and stream flow data. With the type of decisions being made about assimilative capacity limits and increasing wastewater flows and new facilities this data will be invaluable to understanding and modifying model conditions and assessing hydrograph release alternatives. These conditions will be essential to future planning for long term waste disposal options for dischargers. Some evaluation of water quality in the Waccamaw Region and some assumptions about NPS loadings are important to understanding the Waccamaw system's responses. An analysis of rainfall events based upon BCD and Lowcountry STORM models and rainfall data provided by Mr. Purvis at Water Resources Commission lead to a conclusion (verified by John Chigges at DHEC) that a typical maximum summer storm event probably would provide about 10% the annual BOD loading. The loadings were generated by the STORM model which was calibrated for the Waccamaw Region (208 Appendix 7 in the 1978 plan). The drainage basins were modified to better assess future land use changes and keep the calculations more accurate. Most of the drainage areas were reduced to 10,000-20,000 acres (figure 1). Once the basins were delineated then the land uses for 1985 and 2005 were developed for those areas. The land use categories are the same as those developed in Appendix 7. Once the curve numbers were developed for each area, then a series of storm return events were selected for evaluation: 12 Hour 10 Year, 24 Hour 5 Year, 12 Hour 1 Year, 6 Hour 10 Year, 6 Hour 5 Year, 6 Hour, 1 Year. These events were then calculated for inches of runoff by curve number as presented in the (Appendix 7). A new series of graphs was developed for each storm event since the previous study only generated the runoff for curve numbers 30,40,50,60,70,80, 90, and 100 and most of the curve numbers for the areas fall between these. Once this is accomplished we now have the ability to calculate the depth of runoff for every curve number and each of the return events. By multiplying the depth of runoff for a storm by the area then the total volume of runoff can be calculated. The BODs loading can be estimated from Figure 39 (Appendix 7) where the annual BOD loading in pounds per acre per year is estimated based upon curve number. A series of tables was developed to display this information (figure 2). Next, the most likely summer storms were selected. The runoff for present and future land uses were calcualted for each study area. The greatest percentage of increases before and after development in runoff were shown by the more frequent short-duration storms (12 Hour 1 Year) as compared to the less frequent but higher intensity greater volume events (24 Hour 10 years). The runoff increases between the small events is great because the rainfall in a small rain is almost completely abstracted, producing very little runoff, but a small increase beyond this initially absorbed amount almost completely runs off. As an area's curve number increases with development then the amount of water required to saturate the area is significantly reduced and more water runs off the same storm. Thus, we see volume increases of 100-200% with the larger storms, but we see increases of 700-1000% with the smaller storms. A 100% increase in a large storm may, of course, be a much larger volume than a 1000% increase for a smaller storm. If the assumption that 10% of the runoff loading occurs during one of these events then we note that the increase in BOD loading due to changed land use from present to 2005 is about 60%. It is interesting to note, however, that the concentration of the runoff BOD diluted by the runoff varies significantly. The concentration of BOD in runoff after development acturally decreases. The loading increases, but the increased volume dilutes the runoff more. Whether the increased loadings are offset by the increased runoff volume is the question which cannot be answered by an analysis at this level. Only with detailed data to evaluate rainfall/runoff/stream response or a calibrated model which utilizes actual data to calibrate its responses can this issue be resolved. There are, however, observations that can be made. (1) Any area which has uncontrolled urbanization will experience increased BOD loadings and increased runoff; (2) Any receiving waters which do not @dequatelg dilute these runoff waters will be impacted (stormwater ditches, small tidal streams, any stream where runoff will constitute a majority of water). The report"A Report on NonDOint Loadings oijWnter Oualitu---and Assimilative CapacitU'is attached and defines the Intracoastal waterway from Socastee to North Myrtle Beach as the primary area of concern with the Waccamaw River from Conway to the ICWW and the ICWW from 6 to C plant as other areas of concern. It n*st also be understood that the runoff contains other chemicals and materl a] whi ch coul d af f ect bol ta or water qual i ty uses; however, these materl a] s would-probably also be noted in those areas previously discussed as having problems for 13OD/DO. In the Waccamaw Region all shellfishing areas in the Grand Strand are at least conditionally closed, with the majority of shellfishing waters closed at all times. Discussions with Mr. Ken Moore, Manager of Shellfishing Section DHEC indicate that based on their Sanitary Surveys and special studies it can be stated that almost all of these closures can be attributed to cultural nonp-ginj influences. The DHEC shellfish program is producing an analysis of shellfish closures throughout the State and until this report is complete it is difficult to identify and isolate specific problems and causes. Fecal Coliform concentrations in stormwater related to Curve number are displayed in appendix 7 on figure 41. General ly,increases of 20% in concentration of bacteria are expected as land use change from present to 2005. Without controls, the runoff from urbanized areas is high enough in bateria that the inlets of the Grand Strand area could probably not provide adequate dilution to prevent shellfish area closures or will increase the intensity and duration of violations where they are presently occurring. There is no doubt, however, of the impacts and the need for a management program to prohibit runoff to shellfishing areas. Management Agencies Grand Strand Water and Sewer Authority. In April 1986, the Grand Strand Water and Sewer Authority was designated by the Horry County Council to serve as wastewater service provided for all unincorporated areas of Horry County west of the Waccamaw River. This action eliminated the Horry Wdter and Sewer Authority. This group was essentially defunct and all operational activities were already being conducted by Grand Strand. The West Horry 201 Plan as designated by the 208, however, remains in effect. There are, however, several major modifications proposed to this plan as outlined in the "Wastewater Facilities Plan for the Longs and Bucksport Communities, 1986." There have been extensive public meetings and public hearings as well as extensive media coverage of this plan and its conclusions. The plans are very similar for both communities and they both have received very strong Community, County, and State support. There have been no objections raised to date with either of these projects. These areas have both been ranked by DHEC as the number I and number 2 health-hazard priority areas in South Carolina due to extensive septic tank failures, very poor socio-economic conditions, very poor soil types, and in some homes no sanitary facilities at all. The solution proposed is an Innovative and Alternative collection, transmission, and treatment system. The treatment disposal is proposed as land application with a crop to generate 0 & M revenues. The Grand Strand Water and Sewer Authority has been the Designated Management Agency for a significant area East of the Waccamaw River, so there is no need to evaluate their capabilities or responsibilities since they are assuming the full responsibilities of the Horry Water and Sewer Authority. It is recommended through this Update that the Grand Strand Water and Sewer Authority be the Designated Management Agency for the Unincorporated areas of 12 Western Horry County and that the 208 Plan be modlf led to reflect the 201 Plan modi f !cat! ons f or Longs and Bucksport. MANAGEMENT STRATEGY: In order to implement a plan to address the water quality issues addressed " A Wasteload Allocation-and NPS Co-ordination. Strate-gy-for the Waccam-aw Region" has been prepared (attached). This report provides an implementation strategy for addressing NPS pollution in the Waccamaw Region. 24HIOY 12HIY 6H5y 6HIOY 6HlY- CN - #BOD 6.55 1;- 4.03 in 4.65 in 1985 1985 BOD5 Vo I ume BOD5 Vo I ume 8005 Vo I ume BOD5 Vo I ume Sub-basin (2005) (2005) Acres Conc. Runoff f*t! Conc. Runoff Conc. Runoff Conc. Runoff 07-15-03 42 4.3XI04 17,894 10.1 (6.5Xlo7) 105.9 (6. 5 x 1 o 6) 62.3 (1 . i x i o 7) 31*3 (2 . x i o 7) 0 (56) (7.9XIO 4) 8.1 ( 1 .5 X 10 8) 48.5 (2.6XI07) 30.8 (4. 1 X 10 7) 23.7 (5. 3 X 10 7) 194 (6.5X 10 6) 15-02 43 - 2XI04 8,320 10.6 ( "! 3X 107) 211 .8 (1 .5XI06) 62.3 (5. IX106) 33.1 (9.7XIO 6) 0 (49) (2.7XIO 4) 7.1 ( 6xio) 59. (7.2X106) 25.7 (1 .7XI07) 18.1 (2.3X107) 176 (2X I A 05A 4 1 I.5XIO 4 7,040 io.8 (2.3X107) 485 5XI05) 67.7 (3.8xio6 38.8 (6.4xi o6) 0 7) (50) (2.4XIO 4 8.8 (4.3XI07) 100 (3.8xio6 37.5 ( I XI 07) 25.0 (1 .5XIO 0 05B 43 2.8X 104 11,648 10.6 (4.2XI o7) 353 (1 .3XI 06) 55.7 ( 8XI06) 33.1 (1.4Xlo7) 0 (64) ( 7XI04) 4.4 (2.5XI08) 46 (2.4xio7) 26.o (4.2Xl o7) 20.0 (5.5Xl o7) 74.4(l.5Xlo7) 05C 45.5 I.7XI04 6,088 9.1 ( 3Xlo7) 206 (1.3XI06) 49.4 (5.5X106) 29.1 (9..3Xlo6) 0 (61) ( 3XI04) 8.7 (5.7Xlo7) 48 (I.oxio7) 26.5 (I.gxlo7) 2104 (2.3Xlo7) 112.5(4.4XI06) I.BX104 05D 4o 8,032 12.1 (2.3Xlo7) 97.1 (2.9XI06) 44.1 (6.4XI06) (48) (2.7XI04) 9.1 6.13M7) 115 (3.8XI06) -40.5 (I.Ixlo7) 27.3 (1.6xlo7) 05E 41 2.7XI04 12,160 10.8 (4.oXlo7) 485 (8.8Xlo5) 66.1 (6.6X106) 39.6 (I.lxlo7) (47) (3.5XI04) 4.4 0.3XI08) 128 (4.4XI06) 42.6 OM107) 27.2 2Xlo7) Via- 05F 45 4.7XI04 17,6oo 9.5 ( 8xio7) 170 (4.5XI06) 54.1 (1.4Xlo7) 29.8 (2.6xio7) (49) (5.6XI04) 8.8 ( IX108) 118 (7.7XI06) 40.3 (2.2XIo7) 27.1 (3.3Xlo7) 16-61A 41 9.7XIO4 41,984 11.3 (1.4XI08) 0 67.7 (2.3Xlo7) 40.6 0. 3XI o.7) 0 (52) (1.5X10 5) 8.6 (2AX108 ,72 (3.3XI07) 33.8 (7.2XI07) 25.6 (9.5XI07) M.6(i.2XI07) 02-17 43 2.IX104 8,70 10.6 (3.2Xlo7) 35.3 (9.5Xlo5) 55.7 6XI06) 33.1 IX106) 0 (55) (3.7X 104) 9.2 (6.3Xlo7) 74 (7.9XI06) 33.7 (l.7Xlo7) 24.7 (2.4Xlo7) 232.6(2.5XI06) .02-02-HE 39 I.3XI04 5,925 13.2 0.5X107) 11.9 0.5XI06) 48.9 4XI()6) 0 (46) (1.8XI04) 9.8 (2.9XI07) 22.1 OJX106) 53.2 (5.4XI06) 31.7 ( 9X106) 0 02-02-SE 4z 1.9XI04 8.090 to.6 (2.9XI07) 1059. (2.9XI05) 62.3 ( 5XI06) 35.3 ( 9XI06) 0 (54) (3.2XI04) 8.8 (5.9XI07) 70.6 (7.3X106) 32.1 (1.6Xlo7) 23.5 ( 2XI07) 220.6(2.3XI 06) TOTAL BOD5 FLOW (ft3) FLOW (ft3) FLOW (ft3) FLOW (ft3) f985 .104X36.5 55XIV 17.2XI06 .9.2XIV l5.5Xlo7 (2005) .(104X58.5) (129XI07). (139.3X,06) (28.5XI07) (38.6XI07) % increase 61% 135% 710% 1 210% 149% AENT 28 16 29 %.1 IRCE I R S 04 06 02 -6 15 A WASTELOAD ALLOCATION AND NPS COORDINATION STRATEGY FOR THE WACCAMAW REGION Prepared by Waccamew Regional Planning and Development Council to meet the requirements of Section 4B. and C. A WASTELOAD ALLOCATION AND NPS COORDINATION STRATEGY FOR THE GRAND STRAND GROWTH REGION 1. If there is strong evidence that uncontrolled NPS pollutants are impacting uses (shellfishing, assimilative capacity) then the designated NPS and point source management agencies should be evaluated for their existing NPS control program and the possible costs of impacts identified. This should include areas where controls are in place or where development has occurred without controls as well as details of the regulatory personnel and enforcement structure. Once the capabilities of the designated nonpoint source management agency are understood, detailed recommendations should be developed to remedy the problem. Costs should be prepared to evaluate the control programs. 2. In areas identified as potential NPS imapcted areas the procedures should be the same as in areas where uses are known to be impacted. The only difference in approach should be the level of regulatory pressure to implement controls. Once these areas are identified and control programs and costs have been identified, then the SCDHEC, 208 Designated Management Agencies, and the S. C. Coastal Council should jointly evaluate the information and, based on the level of confidence about the source of pollution and their impacts on uses, develop a management plan for each area. These plans should be prioritized based upon cost of implementation and cost of impacts (among other factors). An implementation plan developed among these agencies with time tables and implementation statements would be a part of the Plan. 17 A METHODOLOGY FOR PREDICTING THE IMPACT OF NONPOINT POLLUTION ON WATER QUALITY Prepared by Waccamaw Regional Planning and Development Council to meet requirements of Section 2.8. A METHODOLOGY FOR PREDICTING THE IMPACT OF NONPOINT POLLUTION ON WATER QUALITY The identification and delineation of areas where nonpoint source activities may impact water quality can-be addressed on several levels. There are those areas where impacts are clearly identified as interfering with'classified uses or impacting waste load discharge conditions, and there are areas where impacts may exist and these could be identified as areas of concern and finally there are those areas where we feel confident that nonpoint sources do not presently and will not in the future impact water quality. Almost all the point source dischargers of the Coastal Zone and especially those of the rapid growth areas are at the assimilative capacity of the receiving waters (An exception to this is the Cooper River/Charleston Harbor system and the Beaufort Area). The rivers which feed these systems are usually swampy or intensively farmed and these farms and swamps contribute high organic loads to the rivers. These loads contribute to reduced D.O. levels, especially in those areas where the rivers meet the sea and the rivers slow down and begin to become tidal in nature. This tidal action increases time for BOD exertion and reduces the ability of the rivers to reaerate. As described in the above sections there is no good way presently available to predict impacts of stormwater loads on assimilative capacity without data or a model. The models of Charleston Harbor and the Beaufort/Port Royal areas predicted no impact on the assimilative capacities of dischargers in these waters. The principal problem is that the waters frequently don't meet water quality standards even without point source dischargers much le-ss nonpoint sources. The Waccamaw/Grand Strand ICWW model predicts less than 5.0 mg/1 of D.O. without any point sources due sol + to the extended detention times in the system giving the Low D.O., high BOD and TKN time to exert. The Waccamaw model does not have the capability of 19 of inputting stormwater to assess the impacts on that system. The background conditions described at the beginning of this report frequently originate outside the Coastal Plan,ning areas. For example, the Pee Dee river originates in the Blue Ridge Mountains and drains 16,000 square miles before it reaches South Carolina. There are 2,000,000 people in the Basin with 6% urban and 31% farmed and there are over 300 MGD used by Industries and Municipalities. The problems of trying to isolate the impact of the several dozen square miles of the Grand Strand puts a different light on the problem. The first step in the identification of potential problem areas is the review of all available sources of information and data. The main sources are STORET sampling stations and intensive stream surveys. 1. Water quality monitoring stations: These are usually utilized to develop long-term trend data and are useful to catalogue changes over time since these stations are only sampled once a month. In tidal areas this information is not correlated with rainfall in the drainage area. Station locations are maintained as defined by the maps produced for this study. The prime catalogue of this data at DHEC is S.T.O.R.E.T. and it can be retrieved by all types of parameters, years, and statistical tests. The literature section identified bacteria as the primary pollutant of concern. Bacteria are measured at the WQ stations, but the primary problems are in shellfishing areas which have their own stations and special studies to delineate these problems. D.O. may be a problem in specific areas and other chemicals associated with runoff could also be problems. The water quality stations are a mixture of data sources, since they may contain other data (special studies) mixed in with regular data, so it is recommended that S.T.O.R.E.T. data be reviewed with DHEC personnel before use of this information. It should also be noted that many of the stations at DHEC are located in response to solving point source problems or identifying known or suspected water quality problems. The USGS maintains stations that are primarily flow stations, but some are maintained as quality stations. There are no permanent USGS stations in the tidal areas; however, there are special study stations located in the coastal area. Their regular station data is published annually in a summary report. 2. Intensive Surveys: Intensive surveys are usually short but intensive sampling studies conducted in response to specific needs. At DHEC these studies are utilized to identify specific problems and their causes or to calibrate a water quality model for discharger waste load allocations. These intensive studies data are not always published and may remain in report form so you must ask about specific areas. Mr. Mike Marcus is presently the contact for this Information at DHEC. The S. C. Water Resource Commission has also conducted a limited number .of special studies and these should be reviewed for applicability. The USGS has special studies going on in the Waccamaw Region to identify salt water intrusion, for drinking water facilities, and a mathematical model to simulate their -information. They have previously-conducted -studies 1-ike these in other parts of the State. -The 208 Areawide Plans should also be reviewed.. The technical information In these plans is over 5 years old now, but much of the- data generated is the most advanced and only information available. In some areas this data also contains the only DO/601) runoff relationship data. Once these sources have been approached and data specific to the areas of interest are collected and evaluated then those stations and areas with water quality problems can be identified. A major element in the water quality evaluation of certain waters is the S. C. Water Quality Standards for these waters of concern. In most areas there have been changes in the standards especially in relation to those previously 2 1 classified as swamps, so the water quality information should be reviewed in light of the present as well as past WQ standards. Once the water quality problem stations, problem areas and growth areas are identified then these areas should be noted as existing, potential, or no NPS problem areas. An important element to this is the method to identify future problem areas through existing WQ problems and additional NPS loadings that might be generated by high-growth areas. The literature search and a review of the 208 models indicates that very few NPS Water Quality problems are expected in those areas which were modeled. The reports all identified poorly flushed areas and those strongly composed of stormwater as most likely to have potential problems. The best information on DO relationships exists in areas where dischargers are located or where major system mathematical models are located'(ICWW Waccamaw, Charleston Harbor and Beaufort Harbor). Discharger areas are always modelled and usually they are calibrated using intensive surveys if there are problems in the area. Initially, all Waste Load Allocations for discharges should be reviewed in light of any standards changes and how these may affect future Waste Load Allocations or TMDLs. Another primary factor of this evaluation is the portion of the TMDL assigned to the discharger. If all the TMDL is allocated to pH dischargers and there are also expected increases in NPS loads to these waters, or there are local water quality problems, then these areas should be identified as primary areas of NPS concern. 3. Prioritizing NPS Impact Areas: Once the areas of NPS concern are identified then these areas should be prioritized according to the scale of impact or duration and intensity of impact based on: A. The potential impact on point source TMDL or waste load allocations. 0. The possible: (a) closure of open ShellflShlng waters or M increasing frequency of conditional closures of shellfish areas or (c) continuing closures of areas already closed. C. The continued degradation of impacted waters where point sources presently discharge or increases in existing discharges are planned. 4. Evaluation of NPS ImDacts: In order to define the impact of NPS discharges on water qualitg, and particularly on permitted point source waste loadings where regulatory-level action might be needed, either simulation models or extensive water qualitg date would be required. There are many tUpes of water quality simulation models and the procedures utilized in the application of these are defined the DHEC's Waste Load Allocation Procedures and in the Literature section of this report. It has been stated by DHEC that without a SWMM__Type_r'nodeI'whI_Ch is capable of simulating changes over time and varying flow regimes and the field date nessarg to calibrate these accurately there is Do wag to predict in any useful regulatory manner the possible overlag of NPS conditions as theg mag -affect the low flow water quality conditions that discharger limits are generally set at. In order.to assess the needed modelling work and date collection associated with this work it should be recognized that this is a verg costly undertaking with extensive man-hours required to set up the physical and hgdrologic transport aspects of the model with the cost for these activities easilU exceeding a hundred thousand dollars per COG. collection for calibration of qualitg portions runoff and receiving water models can be approached in two ways. One is to establish a network of station's which are located to adequately isolate primary contributors and which are sampled frequently enough to understand all ranges of possibilities and their Impacts. This method is costly (about $ 10,000 per station) with a minimum of 2 or 3 stations in smaller watersheds and at least several gears data are be needed. 2 Another Method is to conduct synoptic surveys as close to critical event times as possible. These studies can probably be conducted for about $7,000 for each three day study with two surveys being needed at a minimum. These costs of $ 10,000 per station and $7,000 per synopic survey are potentially available at 50% cost sharing with USGS. There are also possibilities that costs for these studies and/or stations could be shared by the dischargers that utilize these waters. The results of these types of data collection methods will be required by DHEC to develop models and data which they would utilize to evaluate NPS/discharger impacts in order to modify any P8rmit/discharge requirements. The use of the data collected by these methodologgs can be utilized for purposes other than modelling. The assessment of data can lead to decisions based upon data analysis alone. 5. Local Manaament Methods: In place of this costly and time consuming data intensive approach,a management methodology can be developed. This methodo1gy could utilize all the steps mentioned dbbQe -With the exception of deQbTbp@Ih'g--ne-w"--'-' models and then try to develop a 208 management approach to control'NP S dIscharges.and their potential impacts. A. Once WQ problems are identified in rapid growth areas with dischargers utilizing the total assimilative capacity, the point source management strategy could be to encourage (a) land application (b) alternative discharge sites. These decisions could be made on the basis of 208 management needs and water quality goals rather than strict water quality criteria. It should also be recognized that NPS control of pollution is also connected to several other issues. Flood control is a major issue in growing areas especially since much new development is pursued on marginal lands. Flood control is becoming a major cost item with local governments and the control of NPS pollution and flood control can be accomplished with the same techniques. The Issue becomes whether the local government subsidizes development by providing flood controls or the developers assume this cost at development. These costs may also be reduced by Innovative planning during development so that development costs may be reduced and property values enhanced. Erosion control is also closely associated with NPS pollution and again controls for one complement the other and local government costs and at times even development costs are reduced with proper NPS control implementation. B. NPS controls can be implemented by local governments to reduce NPS pollution even without specific, costly models and sampling to Identify their impact and costs. These controls can be identified as local goals for local reasons and can be implementedds such. The preferred planning procedure Is outlined in the 4 paragraphs above. The methodology is outlIned)-n the attached flow chart, METHODOLOGY FOR ASSESSING NONPOINT SOURCE IMPACTS Identify Rapid Collect and Evaluate Existing Growth Areas. Water Quality Data Relevant to these areas. Determine - NPS pollutant Determine potential for impaired loading potential by paramater > use in waters impacted by growth based on available literature areas. I denti f y water -b-lses and -No potential pollutant parameters of terminate assessment. concern for each growth area. Classify concerns as low, If D.O. impacts on NPS of concern moderate, or severe by use Classify water body concern as and pollutant parameter. as severe. Proceed to identify stormwater Identify growth areas recommended management activities end local for more extensive Stormwater management agencies for modelling. implementing nonpoint strategies on growth area rated as severe. 2 6 A REPORT ON THE POTENTIAL IMPACT OF POINT AND NONPOINT SOURCE LOADINGS ON WATER QUALITY AND ASSIMILATIVE CAPACITY IN THE WACCAMAW REGION Prepared by Waccamew Regional Planning and Deyelopment Council to meet the requirements of Section 1.C. JUNE 1986 z 7 A REPORT ON THE POTENTIAL IMPACT OF POINT AND NONPOINT LOADINGS ON WATER QUALITY AND ASSIMILATIVE CAPACITY The present land uses and associated nonpoint source loading contribute to background water quality in the Waccamaw Region where the Pee Dee River basin ends after draining 16,000 square miles. The basin begins at the foothills of the Blue Ridge Mountains and over 2,000,000 people live in the basin which is 6% urbanized and 31% farmed. There are over 300 MGD utilized by industry and municipalities. The fact is that in the Waccamaw Region all point source dischargers are presently at the assimilative capacity of their receiving streams due to the nature of the water entering the Region. The proposed increases in future point source flows to handle the growth expected in the Region are layered on this fact. Nonpoint loadings of BOD generated within the Waccmaw Region are expected to increase in a single worst-case summer storm event as much as 60%. Without stormwater controls the overall annual loadings are expected to increase 35%. Nonpoint bacteriological loadings are expected to increase approximately 20% in concentration, but almost all shellfishing areas are already closed due to nonpoint impacts. As described in the Literature and Methodololgy sections, it is not possible in the Waccamaw Region to directly predict the water quality impacts of these loading increases since the system responses are not predictable with existing knowledge and a calibrated model is not available that is capable of simulating these impacts on the DO resources of this region. There are, however, certain assumptions that can be drawn from these observations. Continued uncontrolled runoff from developing areas could affect background conditions for wast e load allocations in areas where the assimilative capacity is totally allocated (all the Waccamaw Region), but we cannot yet predict the degree of impact that might be expected. There is, however, sufficient concern over the potential impact to warrant development of a management strategy to implement nonpoint controls for all new development in order to minimize any further possible impacts that could degrade water quality and cause possible effects on waste load allocations or shellfish closures. Based upon an analysis of flow data and background water quality the areas where assimilative capacity is most threatened by possible future NPS growth impacts are (1) The Intracoastal Waterway from Socastee to North Myrtle Beach, (2) The Intracoastal Waterway from G and M.B. outfall to 'C' plant and (3) the Waccamaw River from Conway to the ICWW. These areas are expected to see the greatest growth in their drainage areas and there are no stormwater controls in place in these areas except for Georgetown County and the Cities of Myrtle Beach and North Myrtle Beach (which predominantly drain to the ocean). The section of the ICWW from Socastee to N.M.B. is of primary concern because this area is expected to grow significantly and the flows in this part of the system are low and move very slowly during dry weather. If any area is directly impacted it should be in this area. The 2 municipaliteis also get their drinking water from this section of waterway. The wastewater discharges of the City 'of NMB and the Grand Strand Water and Sewer Authority A plant are in the lower reaches of this waterway downstream from all development. The ICWW model shows a constantly decreasing background D.O. as water moves through this system with no point source or stormwater inputs. This is caused by the high organic loads and low D.O. of the Pee Dee and Waccamaw Rivers, which because of the long detention times in the system, exert their loads creating ever decreasing D.O. conditions near N.M.B. The model is very sensitive to changes in background conditions creating concern that stormwater inputs could be retained in the system long enough that increased loadings could affect water quality enough to create assimilative capacity problems. 2 9 The area f roM G&MI5 to C PI ant I S the area wl th the greatest assimilative capacity so far allocated. These areas are expected to grow rapidly and the Horry County portion has no, -@stormwater control screati ng a possible impact which could over time af f ect this area's allocation. The area below Conway is of concern because the City of Conway and Grand Strand are expected to raise was.teload allocation to accommodate Conway arpa growth and the GSWSA Central facility's wasteload is daily dependant on background water quality conditions. Impacts which can be documented from NPS are especially noted In shellfishing areas. All shellfishing areas an the Grand Strand are at least conditionally closed to shellfishing and most areas are prohibited to shellfishing due to NPS activities and runoff. Those areas which are presently conditionally closed are subject to full closure as uncontrolled runoff from future developments increases. Especially vulnerable areas are: Little River where there is explosive growth with no stormwater, controls; also the Garden City portion of Horry County which discharges stormwater to Murrells Inlet. Areas which would be of great concern-in Georgetown County are along Murrells Inlet, Midway Inlet,and North Inlet; however, the development in these areas is under the Georgetown County Stormwater Management Ordinance which incorporates technology identified as reducing bacteriological impacts of development at least 80%. There are areas, especially around Pawleys Island that need sewey badly to reduce the negative impacts of failing septic tanks. 3 0 A PLAN FOR FUTURE WATER QUALITY MONITORING NEEDS Prepared by Waccamaw Regional Planning and Development Council to meet requirements of section 3.8. MONITORING NEEDS The a + ge "you never have enough data" is certainly appropriate to the assessment of nonpoint sources of pollution on water quality in Coastal areas. The variable nature of the events and their unpredictability make it extremely difficult to manually sample for impacts or to depend upon stations which are sampled once a month, especially when trying to address duration and intensity of impact. Based on current technology, this only leaves two approaches to data collection, intensive surveys and continuous monitoring. Intensive Surveys. These studies are usually conducted two or three days during "worst-case" times, usually hot-summer, low-flow conditions. These studies are useful to characterize stream segments for mathematical water quality simulations of steady-state water quality, identify discharger impacts, or even identify background conditions. These intensive surveys are relatively simple to conduct in free-flowing streams, but become more complex in the tidal areas since samples need to be correlated to tide stage, and flows cannot easily be gauged based upon typical stream rating techniques. The DHEC Intensive Study philosophy has changed recently with studies including biological assessments as well as chemical analysis. The S. C. DHEC annually conducts about 7 comprehensive intensive surveys for the point source evaluation program. The Coastal surveys scheduled for the future by the 1986 Monitoring Strategy are: - Ashley River/Charleston Harbor - 1986 - Stono River/Folly River - 1986 - Intra Coastal Waterway (Grant Strand) - 1986 - Sampit River 1988 - Ireland Creek 1989 Recent discussions with DHEC personnel indicate that studies are scheduled for the upper Ashley and the Stono River this summer thus, leaving only Battery Creek as an area where surveys are recommended by local 208 staff that are not being addressed by the 1986-1987 DHEC program. A bacteriological survey is also scheduled for Murrells Inlet by the intensive survey group. The USGS has estimated the labor costs of a 3 day survey with field parameters (DO, conductivity, pH, temperature) and basic chemistry (TKN, BOD5, Ammonia and fecal coliform) at around $7,000 per survey. The costs of intensive surveys are difficult to identify at DHEC; however, any studies beyond those scheduled for their normal program are not likely since even with funds they are limited by staff and lab capabilities. Continuous Monitoring. The cost to install and maintain for a year continuous monitoring stations is about $10,000. If there is an existing station, the cost to upgrade an existing USGS guaging station is about $7,000 for adding quality parameters (D.O., TEMP, pH, conductivity). A network of 10 stations has already been installed in the Waccamaw/ICWW of the Waccamaw Region and these stations are funded to operate through this year. It is recommended that these stations be operated for at least another year. The USGS cost estimate to continue to operate this system is $63,000 for another year. The area around Summerville should also be considered for a network of continuous monitors (minimum of 3) at a cost of around $30,000. The need for this network should probably depend on this summer's Intensive Survey's ability to address the problems in the area. The Lowcountry COG has identified Battery Creek as their primary potential NPS impact area and a 2-event intensive survey at $15,000 should provide good preliminary background information. There still needs to be bacteriological surveys of the Hilton Head shellfish areas to identify pollution sources causing proposed shellfish closures, especially as this problem relates to marinas. The Waccamaw Region's primary NPS impacts and needs are primarily in closed shellfishing areas, especially those where sanitary surveys have not been completed. Murrells Inlet is an area of interest since a sewer system has been installed recently and the improvements expected from sewer installation need to be documented. Also, the Pawleys Island area should be surveyed since sewer is due to be installed in this area in order to address sources of bacterial contamination. The costs of all the USGS studies and stations are based on possible 50% USGS match so these costs might be 12 those identified. The possibility of local cost sharing for these studies should also be investigated. In summary, the needs for water quality intensive surveys of DO/BOD are being addressed in the BCD area through the normal DHEC program; however, it may prove useful to install several continuous monitors near Summerville at a cost of $15,000. The Waccamaw Region needs to continue the 10-station continuous monitors for at least another year with match costs of about $32,000. Some intensive surveys might albo be useful on Battery Creek (Beaufort) at a match cost of about $7,000. Survey costs and proposed study areas for bacteriological studies in shellfish areas are in preparation by DHEC and not available for this report; however, the need for understanding the NPS role in shellfish area closures throughout-the State is an obvious need for monitoring efforts. SUMMARY 208 UPDATE 11 Prepared by Waccamew Regional Planning And Development Council JUNE 1906 SUMMARY 208 UPDATE I I This report contains-two 208 Update Reports. These were produced under separate contracts so the work is being kept distinct for contractual purposes. The Update 11 is presented in several sections: A. Total Maximum Daily Loads: The Waccamew Region has received assimilative capacity loads for all major dischargers in the Region. These TMDL's have been changing based on new Standards and Water quality information. There is a need for better monitoring data to understand the flow/quality relationships to define "critical" water quality events. 0. Non Point Source Controls: There has been a new network of monitors installed to assess NPS impacts. It is noted that if Nonpoint-pollution is defined as a problem the separation of designated point/noinpoint management agencies presents management/coordination problems. 1. Regulatory programs: all three Horry County Coastal Municipalities have implemented Stormwater Management Ordinances as has Georgetown County. A Memorandum of Agreement was signed between DHEC and Waccamaw providing for 200 certification of all NPDES, PER and. waste load requests and designates the 208 agency as a coordinating agent. The Primary future regulatory push will be to bring Horry County to Stormwater Management Program. 2. Management Agencies: 208 agency changes completed since the lost Update were: 36 Little River - designated September 23, 1983 for collection and transport only of wastewater. City of North Mrytle Beach - point source designated February, 1984 with an updated 201 facilities plan. It is noted that the flow projections in this plan are not adequate for 20 years and there will be a need to modify the plan in the next few years. Georgetown W ter and Sewer District - 'C' Plant 201 is in review. The new Wachesaw PER is 208 approved to transfer flow from V plant and construct a new 1.2 NGD facility. Myrtle beach - A P.E.R. has been certl f led f or an increase f rom 12.5 to 17.5 NGD. This is only an interim upgrade and no- a] ternatl ves have been devel oped f or di sposal of up to 25 -MGD as the 2005 f I ow. City of Conway - Recently certified to,increase flow from 1.2 -;---.to 2 MGD to meet existing flow8'CdUse-d-U@d-@brl:oading-.@F e expansions will be needed but there are service area agreements and planning issues to be resolved before new flows and wasteloads can be established. 3. Municipal Needs: Local flows are expected to increase from 28 MGD presently permitted to 68 MGD in 20 years. It is stated as the Waccamaw 208 Policy that all private facilities should be eliminated whenever designated agency systems are available or these private facilities should turn over operation and maintenance to the Designated agency as soon as feasible. No new priv6te facilities should be permitted. 4. Urban Stormwater: Local regulatorg programs combined with S.C. Coastal Council Guidelines has strengthened the Waccamaw NPS program. 5. Inventories and Projections: New Land Use and Population projections are contained in this section. 6. Discharger Inventorg: A new list of Dischargers in the Region are provided. WACCAMAW REGIONAL PLANNING AND DEVELOPMENT COUNCIL 208 AREA WIDE WATER QUALITY MANAGEMENT PLAN UP-DATE II APRIL, 1986 39 INTRODUCTION This is the second formal 208 update produced by the Waccamaw Areawide Water Quality Management Plan. The original plan was produced in 1978 and the first update was published in 1951. This report will summarize the changes made primarily to Management Agency designations and will also address population and La nd Use projections for the Waccamaw Region. Appendix I summarizes the conclusions of the previous 208 Update. 40 PROGRAM AREAS A. TOTAL MAXIMUM DAILY WASTELOAD ALLOCATIONS There has been significant progress in this area. The SCDHEC has established waste load allocations for all dischargers, and a Memorandum of Agreement has been signed (Appendix 11) which outlines responsibilities in allocation of wasteloads and 200 certification of permit requests. All TMDL's have not get been assigned bg DHEC. The TMDL concept is becoming more complex as wasteloads are based on flow and water qu6litg conditions other than 7Q 10 conditions. Future needs for these TMDL's and WLA's involve the need for monitoring data to understand the flow/quality relationships to define "critical" water quality events. B. NON-POINT SOURCE CONTROLS In addition to the controls identified in the previous 208 Update there had been significant improvement in non-point regulatorg programs. There has also been a recent effort to upgrade the level and quality of water quality data through a contract wi th the Uni ted States Geol ogi cal Survey to establ i sh 10 Water Qual i tu Monitory Stations in the Waccamaw Region and collect data on 15 minute intervals at those stations for D.O. Ph, conductivity tide, stage, and temperature. This intensive water quality data suplemented by laboratory "wet" information MOD, NH4 etc.) should prove invaluable to understanding the changes created in water quality and subsequent assimulative capacity of coastal tidal rivers and by non- point sources. 41 Presently in the Grand Strand area all major discharger waste loads are at their maximum level (i.e. at secondary treatment or more for ef f f luent flows). The present rate of growth could lead to more than doubling of the existing point source flows with no increase in assimilative capacitg. This irteans for riverine discharges, increased treatment will be required for increased flows. The assimulative capacities of the rivers could be reduced if non-point sources of pollution decrease background water qualitq further or it is found there are other critical periods. The continued separation of point source and non-point source control management agencies, presents potential problems if non-point sources are determined to be a factor in wasteloads in the future and coordinated management is required of the point and non-point loadings in an area. 1. Regulato U_Lrograms: The three principal coastal municipalities in Horry County (Surfside Beach, Myrtle Beach, North Myrtle Beach) have all adopted Stormwater Management Ordinances within the past 2 gears. However, Horry County has not yet developed a Stormwater Management Ordinance or Zoning Ordinance. These Horry County municipalities have joined Georgetown County which has had its program in place since 1983. These ordinances combined with the S.C. Coastal Council's Stormwater Management Guidelines (applicable throughout Horry and Georgetown Counties) have established a program to minimize pollution from developments which meet their criteria. These Coastal Council Stormwater guidelines outline standards for stormwater Retention/Detention based upon distance from receiving waters, and implement best management practices where required. The S.C. Coastal Council Guidelines are primarilarly implemented through their certification of other agency permits. in November 1955, a Memorandum of Agreement was signed between DHEC and Waccamaw COG. This memorandum provided for a formalization of the 208 process as related to certification of NPDES permit requests as well as Preliminary Engineering Reports, wasteload allocations and construction permits. The agreement also describes a coordinating role with other agencies such as the Corps of Engineers and the S.C. Coastal Council. A primary future focus of the 208 program in the Waccamaw Region should be to work towards a stormwater control program in Horry County. Horry C.ounty is presently drafting a Zoning Ordinance which should help control development impacts, and the Planning Commission has formed a Cor6mittee to develop a Stormwater Program. 2. Management Agencies: There have been several changes in De signated Management Agencies since the last Update: Little River was designated a management agency for collection and transport only of wastewater in the 'A' Plant service area and was certified and approved on September 23, 1983. @Ljty of North M,yrtle Beach has been designated a point and non-point source management Agency on February 16,.1984 and has since received a 201 grant to update the treatment facilities. The 201 facilit y under construction is not adequately sized to meet 20 year future flows, so that 43 sometime in the near future a 208 Plan modification will neeg to be submitted for review ang certification. E@Egetown Water and Sewer District is presently working towards implementing a 20 1 grant for *C' Plant. A Preliminary Engineering Report (PER) was also approved by the 206 on February 14, 1984 to develop land application/River discharge system at Wachesaw for 1.2 MGD. 500,000gpd planned for the new facility presently flows to Grand Strand's V Plant. The Garden City Point 350,000gpd would continue to flow to Grand Strand V Plant. The new flows of 1.2 MGD would come from growth in the area plus the recaptured 500,000gpd flow from V Plant. tlyrtle ffeach presently has an approved P.E.R. request to upgrade from 12 to 17.5 MGD, however, the 20 year projected f low of 24 MGD or more has not been addressed by this PER proposal. The present proposal is to treat the additional 5 MGD to higher treatment since there is no additional assimilative capacity at their present discharge site. Future flows must be addressed before any future upgrades are allowed so that a comprehensive plan for growth and sewer disposal can be prepared. Grand Strand Water and Sewer Authority has prepared a 208 approved Master Facilities Plan for all their facilities it) the at-ea. This document contains 20 year projections for the existing primary facilities and 2 projected new facilities. All these facilities are scheduled for upgrades and all three will utilize some form of land application for treatment of some portion of th6 flow. This new updated facilities Plan for Grand Strand contains several changes in service areas for facilities, which are complex and outlined in the Plan, however, an outline is attached (Appendix 111). All these changes were presented at a December, 1965 public hearing and approved by the Waccamaw Regional Planning and Development Council's Board of Directors. Citu of Conway recently was approved to increase wastewater treatment capacity from 1.2 NGD to 2 MGD to meet existing flow requirements. The existing facility will need to be upgraded for ring expansions and future flow increases will depend on water Qualitg monitoring requirements for the recent upgrade and the 20 year projections for the proposed service area. Waste Load allocations for any increases are also not get prepared. There are also problems with service area agreements and these need to be resolved before! any treatment Plant upgrades, since! the service areas-will need to be established before flows can be established an.d.-allocated for waste loads. Town of Loris is presently conducting an evaluation and correction program to rehabilitate the old portions of their collection system. It is anticipated that this correction should allow adequate capacity to meet the town's needc for the future. 3. Municipjal Needs are addressed by the individual 20 year facility plans developed or in the process of development by management agencies and amounts to a change in flows from 26 MGD presently permitted to at least 66 MGD in 20 years. Most private facilities hove been eliminated bq the 201 expansions, however, it is the policy of the Waccamaw 208 program that no private facility can meet the 205 requirements for management, and therefore, should be eliminated when designated wastewater systems are nearby, or these facilities should turn over operation and maintenance to the designated management agency in their service area as soon as feasible. 4. Urban Stormwater: No new data has been developed since the 1980 Update, however, the Nationwide Urban Runoff Program National Report has been released and a report is due in mid- 1986 which will outline the state of knowledge about Urban Stormwater impacts on S. C. Coastal Water Quality. The implementation of Stormwater controls by the Grand Strand Municipalities and Georgetown County combined with Coastal Council's certification - program of Stormwater Guidelines has provided a strong program to prevent any future degradation of water quality in those areas receiving runoff f rom these areas. There have been Yirtually no new stormwater outfalls on the beaches of the Region since these programs have'bee n in place. 5. Inventories and Projections: Populations changes for the Waccamaw Region through 2005 are outlined on table 1. The land use changes expected are shown on table 11. 46 C. DISCHARGER IN'./'ENTORIES The list in Appendix IV identifies all permitted wastewater discharqps in the Waccamaw Region and was supplied by DHEC in December, 1985. There are 6 permitted facilities in Williamsburg County with 2 major municipal discharges (Kingstree, Hemingway). There are 2 small industrial dischargers to the Kingstree facility and one major industrial discharger. Georgetown County has 29 permitted facilities. Thirteen of these are industrial and 7 are minicipal, two are private facilities (DeBordieu and White's Creek) 5 school community facilities are in the County. The two COMMUnity facilities operated in Georgetown County as private facilities are not operated bq Designated Management Agencies. These facilities should be eliminated or operated bq designated Management Agencies as soon as possible. No new permits, expansions or upgrades should be permitted for these facilities until an evaluation of the addressed. feasibility of public operation or elimination of these- facilities is --Horry County has 9 municipal facilities, 5 private community facilities and 12 industrial facilities. The private facilities should be eliminated or operated by Designated Management Agencies. No new permits expansions or upgrades should be permitted for these facilities until an evaluation of the feasible. TABLE I POPULATION PROJECTIONS HORRY COUNTY Census County Division 1985 1990 1995 2000 2005 AYNOR PERSONS Permanent 7,999 8,751 9,546 10,285 11,135 overnight Day CONWAY Permanent 27,349 30,752 34,121 37,412 40,987 overnight ---- Day ---- CONWAY EAST Permanent 12,175 12,573 19,102 22,339 25,934 Overnight 2,612 3,952 5,292 6,632 7,972 Day 14,980 19,443 23,906 28,369 32,832 FLOYDS Permanent 4,054 4,459 4,629 4,920 5,218 Overnight ---- Day ---- LITTLE RIVER Permanent 10,836 12,573 15,548 18,205 20,246 overnight 77,701 88,948 loo.,195 111,446 122,689 Day 17,467 22,671 27,876 32,734 38,740 LONGS Permanent 3,404 3,466 3,685 3,861 3,962 overnight ---- Day ---- LORIS Permanent 12,240 13,697 14,291 15,038 16,298 overnight ---- Day ---- MYRTLE BEACH Permanent 44,567 52,457 62,570 72,222 81,129 overnight 153,782 175,324 194,865 214,907 233,948 Day 27,639 36,575 45,511 54,449 63,384 COUNTY TOTAL Permanent 120,910 139,677 161,073 181,481 201,770 overnight 234,095 268,224 300,352 332,985 364,609 60.069 48 78,689 97,293 115,552 134,aqr POPULATION PROJECTrONS GEORGETOWN COUNTY WACCAMAW NECK Permanent 9,138 11,913 14,024 16,295 18,910 overnight 32,480 39,041 47,302 55,562 63,822 Day 9,394 11,491 13,579 15,684 17,782 GEORGETOWN AREA Permanent 21,240 23,477 24,752 26,303 28,263 REMAINDER OF COUNTY Permanent 17,978 19,010 21,201 23,102 24,425 TOTAL OF GEORGETOWN COUNTY Permanent 48,356 54,400 59,977 65,700 71,598 49 TABLE Il HQRRY COUNTY GROWTH AREA LAND USE-ACRES im 129-Q 19-9 5 2QQ-(l 2005 RESIDENTIAL 16.68 18,729 2032 220569 25-107 CQNMERC I AL 2 163- 2,5a8 3,011 3435 3,856 INDUSTRIAL 1,778 IM7 1,995 2@ 103 2,230 PUBLIC-SFNI- 7 199 7-690 7795 7-9Q 1 8-063 PUBL C OTHER 403,682 400-617 397,986 395,503 392,255 IOIAL- .431,511 431,511 431,511 431,511 431,511 GEORGETOWN COUNTY GRQWTH AREA LAND ME J-9a5 jq_q.Q 199-5 2aQQ 2005 RE51DENTIAL 8,270 9,246 10222 11,176 12,275 COMMERCIAL ---511 553 605 665 725 INDUSTRIAL 1,610 1,738 1,866 rm.E 21,005 PUBLIC-SEML 24,83 25,10 25,369 25,511 25,800 PUBL I C OIHER 213,534 212,081 210,780 209-504 208-037 TOTAL 248 842 248,842 248,842 248,842 248,842 WACCAMAW REGION GROWTH AREA LAND USE 1985 jqq!2 j_g_q5- 2DD-Q 2005 RESIDENTIAL 24,95 27,975 30,946 33-745 -31,M COMMERC I AL 2-67 3,17 1 3,616 4,100 4,581 INDU5TRIAI 3-38Q 3,615 3-861 4-089 4,235 PUBLIC-SEML 32033 32,79 33,164 33,412 33-863 PUBL I C QIHER 617,221 612,698 608,766 602,3 17 -6DQM TOTAL -Eao@= 68Q,353 680,35.1 680,351 680,353 50 - . - . . -.- I I APPENDIX I I 1 51 WACCAMAW REGIONAL PLANNING AND DEVELOPMENT COUNCIL 208 WATER QUALITY MANAGEMENT PLAN UPDATE Waccamaw Regional Planning and Development Council Georgetown, South Carolina January,-1981 This Report was financed through a grant of the U. S. Environmental Protection Agency (EPA) under Section 208 of the Fedei-al Water Pollution Control Act Amendment of 1972 (PL 92-500). 52 Chapter I INTRODUCTION. Concern throughout the United States about the health and economic prob- lems related to water quality helped to prompt passage of the Federal Water Pollution Control Act of 1972. This legislation cited as its objective the restoration and maintenance of the "chemical, physical and biological integri- ty of the Nation's waters". Section 208 of this 1972 legislation (Public Law 92-500) calls for area- wide waste treatment management, preceded by an extensive planning process. -Waccamaw Regional Planning and Development (WRPDC) has been designated by the Governor of South Carolina as*the agency responsible for areawide wa.stewater management planning in Georgetown, Horry, and Williamsburg Counties. As a re- sult of this designation and funding from EPA, an areawide wastewater planning effort has been conducted in the Waccamaw Region with the responsibility to initiate a comprehensive waste treatment planning process and to produce area- wide water quality plans. In addition, Section 208 calls for designation of management agencies to implemen't plans that seek to have the waterways of the Region fishable and swimmable by 1983. WRPDC publish ed the 208-Plan in 1978 which was the culmination of almost- four (4) years of work by,the Waccamaw Staff and three (3) consultants. In - - ' October, 1978 a Continuing Planning Program (CPO) grant was given to WRPDC to continue the planning process and implement the Plan. The following grant (CPP-2) was given to WRPOC in July, 1979. These.work pla'-ns are@_presented in Appendix A (CPP-1) and Appendix 8 (CPP-2),. There are seven (7) 201 Planning Areas in the W accamaw.Region. A sum- mary of each plan is presented in the 208 Plan and a map of these areas is on the following page. 5 3 Al J,(',,C C A D 1,,; 9 c Y. APRIL 1977 WES HO R Y STRAND: 281 Planning Areas Planning Arec?oundary 0 iz HEMI G ID, GEO.@GETOWN" E A ORE Y. 54 %&ff'rCAkAA%,V "`F'Gln'@AL AW3 r@c. vrts,,@@;,,vr :C-f It,ii-11. Chapter 2 SUMMARY OF CONCLUSIONS ANI) RECOMMENI)ATIONS The following sections present a summary of the conclusions and recommen- dations from the 208 Plan and from the work accomplished under the CPP's. 208 PLAN CONCLUSIONS AND RECOMMENDATIONS This section presents engineering and water quality conclusions and recom- mendations from the 208 Plan. Engineering Conclusions and Recommendations A.. Regional Construction Priority Criteria (E8.10) Conclusions and Recommendations: 1. The priority system should be expended to include: a) non-point sources; and, b) to provide a mechanism for ranking all types of projects for use by local and regional officials. B. Structural Source Control and Reduction Options (E8.30) Conclusions and Recommendations: 1. After evaluating the options available it appears that the most feasible alternat-ive for control of existing stormwater problems in Myrtle Beach is through a series of ocean outfalts sized to carry multiple storm s,.ewer discharges away from the beach and well out into the ocean. However, the water quality implications of this needs to be fully evaluated and a detai.led study insti- tuted to prepare the information necessary for engineering design of a control system. C. Regional and Effluent Monitoring Program (E8.50) Conclusions and Recommendations. 1. Existing laboratory facilities in the Region are not adequate to efficiently conduct operational testing or water quality monitor- ing. An inventory of the existing government owned wastewater treat- ment facilities in the Waccamaw Region revealed that many of the facilities utilize private laboratories for sampling and testing and conduct only those tests required for compliance with NPDES permit requirements. Representatives from all the agencies in- terviewed expressed an interest in a regional monitoring program. As the inventory of existing laboratory facilities in the Wacca- 55 maw Region indicated, existing laboratory testing facilities and procedures are not adequate to meet the water quality requirements of the area. 2. It is recommended that a regional effluent monitoringprogram for the Waccamaw Region be instituted. 3. A short-term water quality monitoring program for the Waccamaw Re- gi6n was developed as part of the 208 planning. The Program was used to gather data for calibration of the lower Intracoastal Wa- terway Model. It is recommended that a program for regularly samp- ling these stations be developed as part of the regional monitoring program. 4. Recommended to be included into the regional monitoring program is the sampling of streams upstream and-downstream of significant point source discharges. 5. A regional effluent monitoring program should meet the requirements of the area, provide adeqLtate, efficient sampling and testing at the lowest possible cost, employ qualified personnel, contribute to reaching the water quality goals of the Region, and be acceptabl.e to all the agencies using the facilities. 6. It is recommended that a program of sampling and testing be imple- mented; that is, individual laboratories coordinated by a regional operator. A program as presented w'ou 'ld promote effective, effi- cient treatment plant operation, contributing to the enhancement of water quality in the Region. Coordination of sampling and testing by a regional operator would insure that testing pre-;cribed by the program is conducted and that accurate records of the results are kept. Water Quality Conclusions and Recommendations -Water quality problems studied for Waccamaw Regional Planning and Develop ment Council's 208 program focused on three (3) priority stream segments; the Intracoastal Waterway (ICWW) from Bucksport to Little River Inlet, Waccamaw River from Bucksport to Winyah Bay, and the coastal area from Little River to Georgetown. While water quality problems in Georgetown, Horry and Williamsburg Counties a're not limited to just these areas, sufficient funds were not avail- able for an indepth evaluation of all existing water quality problems. There- fore, these three areas with high priority were evaluated in the initial 208 planning process. Water quality evaluations were based on existing water quality data, addi- tional data collected during the planning process, and a computer model of the Intracoastal- Waterway (ICWW)/Waccamaw River/Winyah Bay :complex from Little River Inlet to Winyah Bay. Based on these water quality evaluations, the fol- lowing conclusions were drawn: 1. The overall quality of water*in the-208 area is good. However, a number of local problems exist, primarily because of munici- pal or industrial waste discharges. General overland runoff 56 with its resulting pollution (non point source pollution) also contributes to water quality problems in some areas of the Wacca- maw Region. 2. The worst stream segment in the area in terms of existing water quality is the Intracoastal Waterway from Bucksport to Little River Inlet. 3. Planned wastewater t reatment facilities, when operational, will result in water quality improvements. 4. The national goals of the Water Pollut ion Control Act Amendments of 1972 (Public Law 92-500) c'alling for fishable and swimmable waters in the United States by 1983 are obtainable in the Wacca- maw Region. Through a combination of controls of point and non- point sources of pollution, an effective program is possible. The most i'mportant regional wate*r quality problems are as follows 1. Bucksport Landing-to Little River Inlet The ICWW between Bucksport Landing and the Little River In- let is a narrow, shallow, man-made channel constructed and main- tained by.the U. S. Army Corps of Engineers. Net velocity i n the channel is very low and estimated detention time of the channel may exceed 40 days during a 7-day, 10-year low flow. Previous studies and current water quality data indicate that this stream segment is frequently subject to water quality violations for dissolved oxygen and fecal coliform standards. Model runs with the ICWW model indicate that point source discharges to the seg- ment should provide advanced waste treatment prior to discharge. The segment receives no major freshwater input for its entire length, for northward flows from-the Waccamaw/Great Pee Dee Ri- ve-r complex. 'A number of swamps drain to the segme nt, however, and previous studies indicate that these swamps may be signif-i- cant non-point pollutan "t sources. The ICWW model indicates that water quality violations will,occur even if-no point source dis- charges were present along the segment. Data collected in the non-point source sampling program in- cates that significant stormwater discharges to the ICWW could result in further deterioration of water quality. It is recom- mended that other alternatives, primarily those involving non- structural controls, be utilized to minimize the discharge urban runoff to this stream segment. 2. The Sampit River The Sampit River is a coastal river which drains a portion of lower Georgetown and Williamsburg Counties. The area drained by the Sampit River consists primarily of swamps, freshwater marshes and abandoned rice fields. Existing DHEC data indicates that non-point sources may be a problem in this istream segment. The.Sampit River also receives a number of point source dis- charges, including municipal discharge from the City of George- town and industrial discharges from Georgetown Steel and Inter- national Paper. Due to the large volume of these discharges and the nature of the wastewater, the International Paper dis- charge has the most significant impact oH water quality. Waste load allocations for this stream segment were not de- veloped in this study. A study by EPA and International Paper is currently being conducted to determine the acceptable level of treatment for industrial discharges to this stream segment. 3. Winyah Bay Winyah Bay extends from the junction 'of the Pee Dee and Waccamaw Rivers at U. S. 17 to the Atlantic Ocean. The bay va- ries in depth from approximately 30 feet in the main channel to less than two (2) feet in more shallow areas at mean low water. The primary water quality problem in this area is shellfish wa- ters which have been closed due to bacterial contamination. Studies are currently being conducted to identify the source of this bacterial contamination. Other problems in the area of the bay include sedimentation and disposal of dredge spoil. The.Pee Dee/Waccamaw River system drains almost one-third (1/3) of the total land area in North and South Carolina; therefore,-much of the'sediment deposited in the bay has been transported long distances. Annual dredging is required at a number of locations to maintain the proper depth in navigational channels which lead from docks in the area of Georgetown to the Atlantic Ocean. The impact of dredge disposal sites on water quality was not evaluated in--this study, a review of data collected in other areas indicates that the impact may be significant, especially with respect to heavy 'metals and pesti- cides. 4. Murrells Inlet Previous studies and water quality data collected and eval- uated in the non-point source sampling program (Appendix 7), in- dicates that non-point sources may have a'significant impact on water quality in the area of Murrells Inlet. Specifically, the oyster beds in the area are closed for a three-day period follow- ing heavy rainfall (in excess of I inch) due to fecal coliform contamination. Data also indicates that recommended criteria may be exceeded for heavy metals concentration, primarily mercury and lead, during wet weather flow. Additional studies should be conducted to better define the frequency and distribution of heavy metals in area runoff. The most probable source of heavy metals is highway runoff. The fate of metals in the marshes of the inlet should also be deter- mined. Excessive levels of heavy metals could indicate s signi- ficant long-term problem; however, existing data is insufficient for an accurate assessment of the problem, and additional data 58 j should be collectec. This is recommended as an area of further study under continuing water quality planning. Data collected in the 208 Program indicates that s(!ptic tanks may be the primary source of fecal coliform bacteria. Fe- cal coliform problems attributable to septic tanks-should be al- leviates upon completion of the planned collection system for the area outlined in the Grand Strand 201 Facilities Plan. Fur- ther development in the area, especially the paving of roads and parking lots and intensive construction of houses and condomini- ums, may offset potential gains in water quality by increasing the volume of urban runoff which typically contains significant numbers of coliform organisms. Urban Runoff to Beach Areas Previous studies, data collected"in the 208 Program, and data from other areas indicate that stormwater discharges to beach areas may represent a significant threat to water quality in coastal areas. Fecal coliform densities in the surf zone of- ten exceed recommended criteria during and after precipitation events. Observed heavy metal concentrations also exceed recom- mended criteria for lead. The primary source of. both pollutants is urban runoff. The limited data available indicates that a more thorough evaluation of storm sewers discharging to beach areas s-hould be conducted. Future planning efforts for new development in coas- tal areas should concentrate on minimizing the increase of stormwater runoff.. Continued increases-in--stormwater discharges may require periodic closing of beaches and greatly increased erosion problems. Both adverse impacts could have a'significant eocnomic impact on the area. Swamps Data collected in the 208 Program and current DHEC quality data indicates that swamps may represent a significant source of non-point pollutant loads. Existing data indicates th.it, in gen-, era] , swamp waters exhibit higher BOD concentrations, higher tem- peratures, higher fecal coliform, counts, low pH, and lower dis- solved oxygen than flowing surface waters in the same geographic area. These freely-flowing surface streams serve as outlets for many of these swamps. Pollutant loads from swamps may be impor- tant under high and low flow conditions. Additional studies should be conducted in the area'o't better define the complex hy- drologic interrelationships between major swamps and area streams. Man's activities may increase the pollutional output of swamps. Although not investigated by this study, it is thought that activities such as timber harvesting and road building may result in increased pollutant discharge from affected swamps. Water quality degradation in natural swamps is largely un- 59 controllable; however, this area should receive additional inves- tigation for better understanding. This research would also pro- vide data for evaluating alternatives to reduce pollutant loads from swamps subjected to timber harvesting and other disruptive activities. In summary, the water quality problems or potential problems discussed above have been identified to date. While other water qliality problems undoubtedly exist within the Region, it has been the purpose of thi-s study to address only those known problems of highest priority. C.P.P. conclusions and Recommendations- A. There is a need for close cooperation and understanding between separate NPS and point source management agencies due to the overlap and complexity of Home Rule and enabling legislation. B. Zoning and subdivision regulations are'es@ent'ial components for effective control of NPS pollution related to growth and development. C. A comprehensive stormwater control program in Myrtle Beach can serve as a model for other communities through the Waccamaw Region. D. The S. C. Water Quality Standards and Classification System should more clearly identify the criteria and procedures-used in defining water quality analyses. E. An approach utilizing non-structural controls will result in immedi-6-te re:L- ductions in stormwater and.prevent the situation from gett_.i,ng any worse. The collector system will require extensive funding and is- more long-term. F. Collection of stormwater through an inteceptor located-in Ocean Boulevard appears to present the best alternative. G. Discharge of collected and disinfected stormwater at one site, (Withers Swash) rather than a diffuser pipe, is the best alternative for discharge. H. The following bb6servations were drawn from the sampling analysis informa- tion gathered during this study: 1. The wet weather surf data contains signific-ntly higher total and fecal col iform counts. than the dry Weatht:r surf data; 2. Class A standards are violated in the surf during wet and dry weather in Section 5. Class SA applies to saltwater suitable for-propagation, s-urvival and harvesting of shellfish for mar- ket purposes; 3.1 Class SB standards are violated in the surf during wet weather in Section 5, but n0t'during dry weather. Class SB applies to saltw*:ter suitable for direct water contact and propagation of shell1fish except shellfish for market purposes;. 60 4. Class-SA standards are 'violated in the surf for each storm e- ve.nt examined; 5. Class &B standards we're violated in the surf for each storm e- vent sampled during peak tourist season (June, July,*and Au- gust). During the nonpeak tourist season, six (6) of nine (9) storm events violated Class SO standards (generally by the 10% requ 1 remen t) ; 6-. The daLta is inconclusi've in establishing tidal influence on coliform counts in the surf; 7. A significant coliform reduction in the surf is observed between 10 and 22 hours after a storm has ended; Comparative stormwater samples collected in surrounding municipal- a 'ties showed that seven (7) of the ei-iht (8) locatio*As had fec I coliform geometric means of greater than 400 counts/100 ml.; 9. The monthly surf data indicates that during the tourist'season, the coliform counts are higher than in the nontourist season;. 10. Street samples collected during peak tourist season revealed ex- tremely high coliform counts: 11. The major source of coliforms found in the stormwater originate from acc'umulation on impervious surfaces; 12. Colifbrms available-for transport to the storm system appear to be proportional to ,the number of people in Myrtle Beach; 13. The'source sampling did not produce any areas which could be called free o.' bacterial pollution. Generally all source samples taken sh6wed consistently high coliform counts; 14. Water quality standards are violated in Withers Swash; 15. The direct beach discharges, natural beach pools, and pipe stream samples-have significantly higher coliform counts.than the surf samples; 16. The wet weat .her direct beach-discharge and beach pool data con- "ains significantly higher total and fecal coliform counts than - ne dry weather data; 17. direct beach discharges# pipe stream, and natural beach pool samples showed high coliform counts during wet weather. The fe- cal coliform counts in the direct beach discharges Wring wet and dry weather conditions combinedo, exceed all present freah- water standards; however, the State of South Carolina has no standards for that type of,water discharge;. 61 18. Reducing the amount of impervious s6rfa 'ces and pavement draining into the storm sevier system should reduce the number of col iforms in the surf; 19. The storin system discharge poses a greater health threat than the surf. Fresh water coming out of the pipes far exceeds public health standards for health protection; 20. There is body -contacr between s torm sewer discharges and people. The greatest potential for health impact5: is in storm system dis- charge regardless of whether the @:tate and/or Federal standards are applied., i.e., pathogens may exist; an.d, 21. Remo val o'f urban stormwater runoff entering the surf'through drain pipes and street runoff will result in water quality im- provement and reduce contact,exposure to the public. Ine stormwater study while analyzing the data and developing the conclusion .that stormwater-discharging bcross the beach creates potential health as well as aesthetic and erosion problems, has identified approaches to reduce and eliminat, the stormwater. The approaches can be divided into two (2) major categori.es:. 1) Structural - representing a technique of intercepting the ex- isting stormva,er generated from roads and other impermeable :;ur- faces and transported to the beach via major storinwater pipes; andf 2) Non-Structural - which will prevent the riunoff from increas-L ing.with development and also can be used-to reduce 'existing .runoff from small sites. This 'approach alsoincludeis ordi- nances covered in 4.E.(b) Regulator-y and Other Programs. 62 0 .APPENDIX Il 63 MEMORANDUM OF AGREE14ENT The intent of this Agreement is to define the responsibilities of the South Carolina Department of Health and Environmental Control (SCDHEC) and the Waccamaw Regional Planning and Development Council (WRPDC) for the review of requests to begin or to continue to transport and/or treat wastewater in the Waccamaw Region in order to ensure their conformance to the Waccamaw Areawide Water Quality Management Plan (WQM). This is a requirement of PL92-500, as defined in 40 CFR Part 130.12(a), dated January 11, 1985. This review will be conducted on all activities which involve SCDHEC review and approval of Preliminary. Engineering Reports, permit requests or plans and specifications for new and reissued NPDES permits; @construction permits; sewage treatment facilities; waste load allocations; pump stations; force mains; and outfall lines in the Waccamaw Region. The flow of paperwork between agencies will occur.as shown in the three (3) attac hed flow-charts for any requests for permits, PERs, or plans and specifi- cations for projects within the Waccamaw 208 planning area. The WRPDC will review these requests in a timely fashion and will certify these requests as to their conformance with the Waccamaw WQM. Plan. Any conflict (which is de- fined as any project which is not addressed by the WQM Plan) will be evaluated by the WRPDC and the WQM Plan will be modified or the plans modified as may be necessary to meet the intent and goals of the WQM Plan. No permi ts or approvals that are in conflict with the Waccamaw WQM Plan will be issued by SCDHEC. U R 2:5 19B5 64 a vn' LvIx s I's, WRPDC staff will develop a tracking system to effectively check the status of the requests and the WRPDC will endeavor to comment on all projects in a' timely manner. Any projects which are in conflict with the WQM Plan will be addressed by modifying the request or modifying the WQM Plan. WQM Plan modifications will be addressed by public hearings and local government agency reviews. All WQM Plan changes will be approved by the WRPDC Board of Directors and forwarded to the SCDHEC for concurrence and certification to EPA when necessary. The locally affected planning commissions will also be provided with all requests for certification in order to meet the intent of 1976 Code of Laws, 6-7-570. The WRPDC will act as a coordinator for other 'agencies certifications of permit requests to include but not limited to the South Carolina Coastal Council. The SCDHEC will 'provide the WRPDC with Total Maximum Daily Loads (TMOL) for those "priority" segments defined by WRPDC for immediate needs. The other TMDL's will be provided on an "as needed" basis by SCDHEC. The formulas for allocation of the TMOL's will be developed and implemented by the WRPDC and submitted to the SCDHEC for their concurrence. The WRPDC-staff will.work with SCOHEC and the Designated Management Agencies to develop and implement an ongoing study of the "critical" water quality limited segments in the region to define and refine the water quality data used for allocations. The WRPDC will revise and update the WQM Plan for the Waccamaw Region annually if necessary. This update will reflect the changes which have occurred over the past year. Population projections, treatment plantflows and locations, major Pump station and force main locations, and Management Agency Designation ?VY Responsibility updates will be included in this WQM plan update. 0 ; 65 This Memorandum of Agreement will be revised and updated as required to meet any changes in regulatory requirements or local needs. Robert G. Gross, Chief Ken'Thompson, Executiy@ Director Bureau of Water Pollution Control Waccamaw Regional Plaiining and Development Council '20 (Date) (Date) 66 APPENDIX III 67 Chapter 1 EXECUTIVE SUMMARY The Grand Strand Water and Sewer Authority was created through state legislation to provide future protection for surface and groundwaters in unincorporated areas of Horry County, east of the Waccamaw River. The Authority is governed by a Board of Directors currently chaired by Mr. George R. Vereen. The Executive Director for the Authority, Mr. Douglas P. Wendel, manages operation of the Authority which is staffed by over 60 personnel at the present time. The need for a Plan Update is evidenced by the rapid growth in the Authority's service area. The first plan prepared for the Authority in the early 1970's is now out of date with respect to projected population and flows. Therefore, the Authority commissioned.this Wastewater Facilities Plan Update in 1983. The Planning period for this update extends from the year 1985 through the year 2005. This compares with the original plan, which considered a period extending only through the year 1997. The service area for the Authority has been officially revised from time to time to meet the changing needs__6f the entire Grand Strand region. As currently defined, the service area encompasses that portion of Horry County east of the Waccamaw River except for the Myrtld Beach.and North Myrtle Beach areas, plus a portion of Garden City Point in Georgetown County. This service area is divided into three service subareas. The South Strand service area is generally that area southeast of the Waccamaw River and the Intracoastal Waterway, south of Highway 501. The Central Strand Service Area is bounded by the Waccamaw River and Conway on the south and west, the Intracoastal Waterway on the south and east, and the Seaboard Coast Line Railroad on the north. The North Strand Service Area extends from this point to the North Carolina state line. Population projections for the Plan Update are based on the 1980 Census of Population and County land use planning. Permanent population was projected within the state-bounded limits for each of the four CDD's comprising the Authority service area. This projection resulted in a permanent population of 98,680 by the year 2005. Overnight and day visitors are projected from historic growth in the region for each of the four CDD's. This method resulted in a year 2005 projection of 143,980 overnight visitors and 165,200 day visitors. 68 Wastewater flows for the planning period were developed from the population projections and unit waste flows recommended inthe original Environmental Impact Statement. These unit flows included 100 gpcd for permanent residents, 50 gpcd for overnight visitors, and 25 gpcd for day tourists. These determinants resulted in flow projections for each of the three Grand Strand service subareas. By the year 2005, it is estimated that the Authority will be managing a total of 21.3 mgd of wast-ewater flows. A water conservation program was initiated by the Grand Strand Water and Sewer Authority in 1983. This is a Countywide program, representing a long-term commitment by the Authority to promote water conservation throughout the Grand Strand region. This will result in reduced wastewater flows, the magnitude of which will'not be quantifiable for a few years. An environmental assessment is presented in the Plan Update addressing climate, topography, geology, sensitive areas, socioeconomics trends, water resources, existing facilities, and potential environmental impacts of plan recommendations. Attention is focused on water resources, both surface and groundwaters, to maximize protection of the Grand Strand's valuable water resources through appropriate wastewater management methods. Existing wastewater systems in the Authority's service area include the Baytree WWTP (planned-to be taken out of service in September), Little River Welcome Center WTWTP, and the Interim North Plant A in the North Strand Service Area; the TEC WWTP in the Central Strand Service Area; and the South Strand Regional WWTP (Plant G) in the South Strand service area. These facilities are described in the Plan Update and their future use is carefully considered in the development of recommendations for future wastewater management methods for the Authority. Wastewater management alternatives were developed considering present and future conditions in the service area. This resulted in the development of the following alternatives for detailed consideration: South Strand South Strand 1--Secondary treatment with effluent discharge to the Waccamaw River supplemented with land application in the summer. South Strand 2--Secondary treatment plus filtration with effluent discharge to an aquifer recharge system. 68 South Strand 3--Secondary treatment plus filtration with effluent discharge of the Waccamaw River. Central Strand Central Strand 1--Secondary treatment with effluent discharge to the Waccamaw River, supplemented with summer irrigation. Central Strand 2--Secondary treatment with effluent discharge to wetlands. Central Strand 3--Secondary treatment with effluent discharge to rapid infiltration. Central Strand 4--Secondary treatment with.combined discharges (per above). North Strand North Strand 1--Secondary treatment with effluent discharge to Carolina Bays. An evaluation of treatment methods was conducted to select the most cost-effective means of secondary treatment for each service area. For alternatives requiring advanced secondary treatment, a continuous clean shallow bed gravity filtration system was selected, based on past experiences with various types of filtration systems. The cost-effectiveness evaluation for the treatment/ disposal alternatives considered present worth, process stability and flexibility, ease of operation, safety of ,operation, energy demand, utilization of existing facilities, environmental impact and innovative/alternative technology classification. Based on these considerations, the following recommendations were developed: South Strand--Expansion of existing facility to 12.7 mgd using a modified rotating biological contactor (RBC) secondary treatment Process. Effluent disposal will be by Waccamaw River discharge per the wasteload allocation, with excess to golf course irrigation and the Authority's sod farm, all in proximity to the facility. Central Strand--Aerated lagoon secondary treatment process, with ultimate capacity of 4.9 mgd, with effluent disposal by golf course irrigation and onsite land treatment, supplemented by wet-weather discharge to the Waccamaw River. 70 North Strand--Aerated lagoon secondary treatment process, with ultimate capacity of 3.7 mgd, with discharge to the Carolina Bays (the 201 Amendment already completed and approved for the North Area recommended these facilities, of 2.5- and 1.2-mgd capacities). Wastewater conveyance systems are also considered in the Plan Update. The necessary interceptors, pump stations, and force mains required to serve the three service areas are located and sized on a preliminary basis to provide for orderly system development. Phasing for-these systems is addressed to provide service as appropriate to best match anticipated development. The solids management system for the Authority's planned facilities is addressed in detail. The present system at the Authority's South Strand Regional WWTP includes a sod farming operation preceded by anaerobic digestion. In light of the Authority's significant investment in this system, the success of the system to date, and the availability of land to readily expand this system, it is recommended that the sod farm operation be expanded to service the future facilities. Implementation of the 20-year Wastewater Facilities Plan Update is based on present development and local knowledge relating to planned development within the service area. The plan calls for phased construdtion of the waste@rater facilities to satisfy the growing needs of the area as these needs are realized. Based on order-of-maghitude capital costs and operation and maintenance expenses, estimated impact fees and user charges for future years are presented for further consideration. gnR172/14 PAGE ACTIVE FACILITIES IN W.ACCAMAW COG -PR I IVA FLOW ACTUAL RECEIV NG STREAM SEGMT PLANT FLOW WATERS CLASS BASIN SEGMT CLASS FACILITY NAPE COUNTY TY(E WL A r. 1. 0 1:1 --------cAMP IT-,Rv- sr_---o 347 0 @o A itl AVA IIESS-CURP-ZCECFCET(3WtL-GEORGE-ICW ----I '- 0 SAMPIT RV SC 030702 04 W L C -7 AiFll(AN CYANAt:ID CUMPANY GEOPCEIC4N I t' T A 030710 12 I C 1 3" A-4m kv S IL-N Of CLURC-LTOWN 16. Ll 2.0 cooo5bri LESTER CK- A I ... 4@;It:! FEI-kY SCH()LI GIGRGE7OWN (0 LANES CkEEK U000350-SAMPIT RV sc-030702-016 W I CA 2( L INA LIf IN1NG L Ll1-lkIV..-CLLfGEl('wN I N -I CtitIf I f L SCht,( L/GE(A@CE. IWN SCH GEON(ILTOWN vu .01 ocooolo ChOPPEE CK VI-BLACK RV T A 0.30706 06 -9 141; wL:0 tt@EEK CLE14 S0 /GEONG7 @,N GEOkGE 7CWN PU 0.015 EOSSER SWP-PCRT CK- T 8 030724 01 E WACCAMAW RV IR T A 030702 06 E (-j of,.61 C-'-W1.t/HAGL1% PLANT GI:ORCr I 04N @'U .05 EY CK-SAPPI-T--RV SC 030702-15 W SC((2t!711 GC4LE.A/HAk@'Gt,.Y HILLS t,@liP..-----GF.QRLElojtr.-Ie.U-0.100-.OOOO036-7UPK GC-;1EA/LIIC11fILLr) FLAVT C GE`06GEICWt! Pu 2.b 0000200 CHAPELS CK- T A 030702 02 W! I-IC141 '-I/L 1 101.1 II.LL1 I L ANT C GE Or'('E I cwtq vu WACCAMAW RIVER -WACCAMAW R V T A 030702 02 W .SC(' C 1" GCwl !AIL I T(hF ItLD FLANTAT ION C E U R G E 10 w t, M. U .02 CHAPEL CK SL( ( c 4t Ot, G C 0 1 ! A /w Z L C, C f I E L D F L P I, I A T I ON GL OR GL I Cd N --- --- MU -.4 - -.-------L-LACK RV - - -- A 030706--03-E c I ( cil';@ GE61 CE TOoll C I TY OF GE ORGE I OWN vu INI'L PAPER CO CANAL 16.) #26 (.FO1-(.f 10414 SIAINLrtS VFG r1Eow(1E7C1WN IN 0.015 CANAAN BR D1- TSC 030702 38 W @((CC1431 GEjFCFTCWN STEEL CCRP GEOkGEIC'dN IN 2.04 0000420 SAMPIT RV SC 030702 .04 w S((C(JC7I G---'I(-ET04N SILEL/FLF-F,EDUC.-PL-T-GLL]kGCTCWN.--,It,-.4b----- - - -SAMP 17- R V- -SC----0307G2@04-W GEDI CL IN PLANT GEOPGE T(14N wu 3.5 000letOO @,HITES CK-SAPPIT RV TSC 030702 16 E Z@ C C j!j ('qLtr !C'4rs f-Hp GE(jRGE7C4N PO .02('1 0000001 6 MILE CK-5LACK RV T B 030706 0 71 W :i(( Ofc;v I 4111@1.tTllut@Al- PAPLF' CUPPANY GFOfCEICwN IN 18.0 0030000 SAMP17 RV Sc 030702 04 W @C(C(Itl;; !I . I CjiL:!'IC/-.LF,/At:LF.EhS PLT ---GLCRGEICWN IN-13-000C130 J0104SONS SWP-DI- -8-03 0 710-1 1 - W ZCC(.. 47@1 !1APlk7TA/GFUFGETOWN GLIA 6EURGElOWN I N 13.82 SA141EE RV 8 030602 20 w -3 Z:@' L C C ?e, U*4CIII KNIIIING Mlil-S/ANDREWS GEOFIGE7fj,.qN IN LESTERS CK % L C C 0 25 P 14 % I t VS P 11. P V I LLA(,L I NC GEORGE 1OWN Pu .01b ATLANTIC OCEAN SA 030704 01 W .@Cf.-t IJI PLEj@!.fitql` t-ILL HS/C1ORGL7WN S C.H- GE OUGr. I CW N.- MU -.0 18---- ROSSEW SWP t)]-POI;T-CK------T-H 030724 01-E- EL!I,. ',Ch/GE(FZGFTWN SCI: 6 1: OR G E 7 OW N V U .0 1 KILSOCK BAY DI-SAMPIT RV TSC 030702 04 w S C .3 SC i @ Y CEVT/( C(!RGElCWt- SHOP GEURCIf TCwN I N FEE DEE. RV MSH DI 7 B 030702 03 w S C( 1 24 71 'LC $ L I L I @ !1 F, /V I NYAH STE AM 5 1 A GE ORCt I CNN It, .0cit TURKEY CK TSC 030702 15 v @i@( L @t I I I VVV (L1wPJf,A1I(,1j IN-.00402---- - - -.-- @@ANIP 11 - kV ----SC-030702-0 4-W '@Ct( '0732 v-411E C-LINCL tj@,HR/CARDL INA W7& GEC)kGETC-iN %lu . I.-t WHITES CK DI-SAMPIT RV TSC 030702 16 W sccc 4( -6 AVX CtRA11'ICS C014P Howky IN .02 0000020 W17HERS SWASH- TSA 030704 15 W 5 L r 0 J j'ib A YI-1 L L A UNLA CP AT hORRY- IN .005 0000 001 PILL BR DI T A 030718 07 kv $ CL ( -@ i i 07 j? 4 KI 1. L R OC M I Y-.---, I N-.- -- - - -- - -- JENK INS - S*AWP --- :@ C(, L 1- 139 d r- L t ( CREEK VINE HURP Y IN fULLET CK SC(V;'jt-J0 CCO;4, CP,7U?'. V ILLACE hc:'pHy I N I.t INTERCOASTAL WATERWAY A 030715 Ob W CEL,1733 (J14'@AY/L))(I[)AlIUN FICt-D 473 HURRY V U 1.2 0000250 WADUS LK-WACCAMAU RV 7 A 030716 18 W SC( L 1-3,14U C. ?. @- C O'@'- I R L C T I ON C M I N I N (i- f! C Rh -... . 111; ---. - - - - - . ' S IL ( ( (I j 0!@9 G!k I t ( IF I C./CI NWAY F L 7 HLRPY IN .0001 IPACCAMAW RV DI A 030,716 01 E SL( ( 40 16(o Gi-I@A/CA@@(- LAV PILOT PGM HORRY V@u UNNAMED DITCH !; 4-C. ( d, 0 4 10 CS o I E it /C E N I Nt L R V F L T HO WN Y MLI WACCAMAW FfV WE'll-ANDS -PL7--HLjRRY---.-.- Pu WACCAMAW - liV- WETLANDS ac(lo 4 76 CAfi[LINA IEC HORRY MLI 1.2 00OC175 IAACCAM.AW RV DI T A 030716 01 E 5(.( !4',] PLT A "OQwY VU !.7 IN714ACOAS7AL WATERWAY SA 030715 05 W S (, C 2 7 -s',3 PLANT HORN Y k'U 1.5 WACCAMAW RV ASWP 030702 02 E t.C ( u ! ', @ -s t@ @, I t A / I F (. I- I LL I .. F'L I HORN Y t U ---- - UACCAMAW RV-WETLANDS-------- S L( L -"I; f 0 t. I N 4 ! 1 0'. v I f. I NG CLI@ P AI;Y f i UN F< It 1 N JENKINS CK I A 030-118 08 W b( ( C 17-) L I T IL I ri I %,( 1, WATE R' & SE:%EQAGE HURRY I N) .0008 Dk A I NAGE D I TCH 030715 05 W @c,( c t J-@ I! TO,!. Ut 11ORky 11(1 .27 PLEASANT HE: ADOW SWP 8 030718 10 W 4(; 7;') A :-(. t - L. I)tEt. (U/MINE. PI IiORN Y SLAR SWAMP ill I $--C 4(fl/tIAIN F LT-NEW liE)QfY U 12.0 WACCAMAW NV ASWP 030716 01 E I N INTRACOASTAL WW 1'.@ACII/hA)Ek I'Ll HuRky 4/ 2 4 ACTIVE F ACILITIES IN WACCAMAW COG PAGE- 2 PRI TAR_y PLANT FLOW @ ACTUAL RECEIVING STREAK SEGMT EL Ni)Lf S No FACILITY NAME COUNTY TYPE WLA FLOW WATERS ASS BASIN SEGMT . CLASS SC(:C221tI N 14NP7LE- fir A(H/CRE SCE-.kV-BE-AC-P----44ORRV-------,MU----2-1---O()00525--4-NT-RAC-G#,STAL--WA-TE4;@w A* A SCOL,"'2 It2 N MNPILE I'VAcH/ccrim mivi PLI HORAY mu 3.4 0000725 INTRACOASTAL WATERWAY A 030715 05 W SCCL324bo PIP41 %,ALLFY ESIATLS "URRY ?ju .0477 %ACCAMAW pv TR TA 030716 01 E 10 RUM rluFF Vilf/LTL F-.IVER WTR ViONRY pl) .6 JwACCAMAW RV .A 030716 02 rt t;L.CC'-t4t,b i%,Y W AC C AMA W-R V-0 -A-- 030 716-01--. C DE $:1 0 NIP A Y S ( t C @'e 1444 SC I W, V DE F'T/VE LCn 1,1 C IR -L I T PV HURRY M u .0075 FlULLET CK TSA 030715 04 W IN. 66.3 A 1 030716 01 E SL( C(. 1 104 SC JULLIC SLR/CRAINGER STEAM HORkY VACCAMAW RV SCI C33014 SHELLY ACRCS SD/GRAHAIJ CONST HORRY Pu .01 0000001 MILL BR-CHII@:NERS SWP- TA 030718 07 W SCEEL.24t4 UN I lk U - ME14lLH_Z,-MF C-/-C0NUAY-PL-T--)40RWy ------------ 4 J@_ 15 MAPLE-SWP T--A----O 3 0-7 16 .6 S C (, C 0 2 C,; 7 IJS tlF@ FO;,Cr/MYR7LF UJEAC14 AFE, H(jRRY M. U .75 INTRACSTL WTWY A 030715 05 W S(C( @s421 w A @IST/FILL QIRI HORRY IN COLLINS CREEK SWAMP TA 030716 01 E 0. S C CE C ? -2 El" %JL@l 1@ INE I VASS WCAKS HORRY IN 0.130 0000127 SOCASTEE SWP Of TA 030715 03 W @.CCLI.JM A@k Ill N L t ARSOUPC- It.; ---- t@( ( C ( 3 123 GISI-IROCAUES USA WILLI AMSBUI,G IN 2.275 .0002275 BROAD SWP 7R- IA 030710 10 W k N WILLIAMSOL11,G 1ju .4 MUDDY CK- 8 030724 04 W I Cj OF COO c: I t 95 H 'W. I EC WA Y SLCL,39r.34 HEM 1 NCON AY TOkN OF WILLIAMSBUI,r. MU CLARKS CREEK. t! CC C 54@ 7L W I LL I AM SOURG- 14LI-2-1 5 13LACK A-0 30 710-0 1- F K 114( 1. 1 1;F C Ytrk - PL ANT- -RV C C V J493 MILL IFEN C. CV/11INGSTREE MILL WILLIAMEBUkG IN .276 ULACK RV TA 030710 01 E S( ( c_tdo_'9 SC I%Y DEPT/P INGS'lklE W ILL] AMSOUV6 I N BLACK RV SWP DI A 030710 0 1;:.. E dba ')F,DS PRINTED 7u REC, 3 6668 14109 7990